In an attempt to keep India’s regional navigation satellite system fully operational, the Indian Space Research Organisation (ISRO) is preparing to launch a back-up for IRNSS-1A, one of the seven satellites in the constellation, that has been hobbled by the failure of the atomic clocks on board.

The PSLV C39 mission, scheduled for late July or early August, will carry the new satellite named IRNSS-1H into orbit, K. Sivan, Director of Vikram Sarabhai Space Centre, told The Hindu.

A priority

Replacing IRNSS-1A became a priority for the ISRO after it was confirmed in January this year that all the three rubidium atomic clocks on board had stopped functioning. The space agency had decided on launching one of the two spare satellites after initial efforts to restart the clocks failed.

First of seven

IRNSS-1A is the first of the seven satellites comprising the Navigation Indian Constellation (NavIC), a multi-purpose satellite-based positioning system, envisaged as India’s alternative to the American GPS. NavIC has been designed to support vehicle tracking, fleet management, disaster management and mapping services besides terrestrial, marine and aerial navigation for India and its neighbourhood.

The system became operational in 2016 after the seventh satellite in the series was placed in orbit.